1. Field of Invention
The present invention relates to a digital logical circuit. More particularly, the present invention relates to a shift register.
2. Description of Related Art
The shift register is a widely used digital logical circuit. For example, the shift register plays a key role in the driving architecture of the flat panel display.
Referring to FIG. 1, FIG. 1 is a circuit diagram of a conventional CMOS shift register circuit, applied in low temperature poly silicon (LTPS) technology and implemented upon a glass substrate. The shift register circuit mainly comprises multiple-stage latching circuits 101 and logical circuits 103 in serial connection. Wherein, each latching circuit 101 in a stage is consisted of six transistors, and each logical circuit 103 in a stage needs four transistors.
However, as all of the electronic devices tend to be small size in the information-exploding modern life, the flat panel display is required to achieve high resolution to satisfy customer's requirement in addition to the mini size. Therefore, although the shift register in FIG. 1 can achieve the necessary native function, each shift register of the circuit needs ten registers. The large-scale circuit design is certainly not suitable for the requirement of the evolvement of the modern technologies.